MECHANICAL ROCK BREAKDOWN DUE TO DIURNAL SOLAR EXPOSURE: RESOLVING A PARADOX BETWEEN OBSERVATIONS AND THEORY

2017 ◽  
Author(s):  
Peter Mackenzie-Helnwein ◽  
◽  
Bernard Hallet
Keyword(s):  
Author(s):  
Camila Roos Mariano Da Rocha ◽  
Agatha Hofmann ◽  
Gabriela Spessatto ◽  
Georgia Chichelero ◽  
Luiza Alves Nabarros ◽  
...  
Keyword(s):  

Solar exposure: knowledge and habits of Agronomy students


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2314
Author(s):  
Ana Margarida Silva ◽  
Diana Pinto ◽  
Iva Fernandes ◽  
Victor de Freitas ◽  
María de la Luz Cádiz-Gurrea ◽  
...  

During kiwiberry production, different by-products are generated, including leaves that are removed to increase the fruit’s solar exposure. The aim of this work was to extract bioactive compounds from kiwiberry leaf by employing microwave-assisted extraction (MAE). Compatible food solvents (water and ethanol) were employed. The alcoholic extract contained the highest phenolic and flavonoid contents (629.48 mg of gallic acid equivalents (GAE) per gram of plant material on dry weight (dw) (GAE/g dw) and 136.81 mg of catechin equivalents per gram of plant material on dw (CAE/g dw), respectively). Oppositely, the hydroalcoholic extract achieved the highest antioxidant activity and scavenging activity against reactive oxygen and nitrogen species (IC50 = 29.10 μg/mL for O2•−, IC50 = 1.87 μg/mL for HOCl and IC50 = 1.18 μg/mL for •NO). The phenolic profile showed the presence of caffeoylquinic acids, proanthocyanidin, and quercetin in all samples. However, caffeoylquinic acids and quercetin were detected in higher amounts in the alcoholic extract, while proanthocyanidins were prevalent in the hydroalcoholic extract. No adverse effects were observed on Caco-2 viability, while the highest concentration (1000 µg/mL) of hydroalcoholic and alcoholic extracts conducted to a decrease of HT29-MTX viability. These results highlight the MAE potentialities to extract bioactive compounds from kiwiberry leaf.


2017 ◽  
Vol 137 (5) ◽  
pp. S45
Author(s):  
B. Ngo ◽  
E. Raynaud ◽  
S. Victorin ◽  
S. Brizion ◽  
T. Baldeweck ◽  
...  
Keyword(s):  

2010 ◽  
Vol 53 (1) ◽  
pp. 239-247 ◽  
Author(s):  
K. G. Gebremedhin ◽  
C. N. Lee ◽  
P. E. Hillman ◽  
R. J. Collier

Author(s):  
Scott Pokswinski ◽  
Michael R. Gallagher ◽  
Nicholas S. Skowronski ◽  
E. Louise Loudermilk ◽  
Joseph J. O'Brien ◽  
...  

Firebrands are an important agent of wildfire spread and structure fire ignitions at the wildland urban interface. Bark flake morphology has been highlighted as an important, yet poorly characterized factor in firebrand generation, transport, deposition, and ignition of unburned material. Using pine species where bark flakes are the documented source of embers, we conducted experiments to investigate how bark structure changes in response to diurnal drying. Over a 3-day period in a longleaf pine (Pinus palustris Mill.) stand in Florida, we recorded changes in temperature, moisture content and structure of bark across different facing aspects of mature pine trees to examine the effects of varying solar exposure on bark moisture. We further compared results to bark drying in a pitch pine (Pinus rigida Mill.) plantation in New Jersey. Under all conditions, bark peeled and lifted away from the tree trunk over the study periods. Tree bole aspect and the time of day interacted to significantly affect bark peeling. General temperature increases and moisture content decreases were significantly different between east and west aspects in pitch pine, and with time of day and aspect in longleaf pine. These results illustrate that bark moisture and flakiness is highly dynamic on short time scales, driven largely by solar exposure. These diurnal changes likely influence the probability of firebrand production during fire events via controls on moisture (ignition) and peeling (lofting).


2015 ◽  
Vol 55 (4) ◽  
pp. 13-22 ◽  
Author(s):  
Aliya Z. Jiwani ◽  
Louis R. Pasquale

2018 ◽  
Vol 25 (2) ◽  
pp. 124-128 ◽  
Author(s):  
D. Y. Kim ◽  
T. M. Ahn ◽  
Y. C. Kye ◽  
S. H. Seo

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